Disable players from using colors in chat?

How can I disable players from using colors in chat? I put Herochat on my server, and there is a permission to allow chat colors for players, but they seem to still have access to type colors without it. I tried removing all plugins to see if something was clashing and it would let players type colors in chat no matter what. I have seen another server that prevents this, so how would I go about doing this?

 

Try giving them a negative permission for colour usage. <channel> being the main/default channel (or global)

PermissionsEX

Code:

- -herochat.color.<channel>

PermissionsBukkit

Code:

herochat.color.<channel>: false

bPermissions

Code:

- ^herochat.color.<channel>

 

mChatSuite can do this and mChannel can be used for channels. Check it out.